
Take her to the vet to be assessed & your vet may be able to give you advice, or if the vet thinks it neccessary they can refer you to a skin specialist who can run some tests to find out what is causing the itching. Skin problems are not always easy to sort out & sometimes it is process of elimination. Food trials etc.
Unfortunately some breeds are prone to skin problems.
Hope this is helpful.
PS is she up to date with flea control treatment?